Related papers: Ground-state properties and superfluidity of two- …
Using large scale quantum Monte Carlo simulations of lattice bosonic models, we precisely investigate the effect of weak Josephson tunneling between 2D superfluid or superconducting layers. In the clean case, the Kosterlitz-Thouless…
We experimentally investigate the superfluid properties of a two-dimensional, weakly interacting Bose-Einstein condensate in the zero-temperature regime, when it is subjected to a triangular optical lattice potential. We implement an…
Thin $^4$He films adsorbed to weakly attractive substrates form nearly 2D layers. We describe the vortices in 2D superfluid $^4$He like quasiparticles. With the aid of a variational many-body calculation we estimate their inertial mass and…
We consider the ground state of a bilayer system of dipolar bosons, where dipoles are oriented by an external field in the direction perpendicular to the parallel planes. Quantum Monte Carlo methods are used to calculate the ground-state…
The rapid progress in the production and cooling of molecular gases indicates that experimental studies of quantum gases with a strong dipolar interaction is soon within reach. Dipolar gases are predicted to exhibit very rich physics…
The superfluid-crystal quantum phase transition of a system of purely repulsive dipolar bosons in two dimensions is studied by Quantum Monte Carlo simulations at zero temperature. We determine freezing and melting densities, and estimate…
We have studied the role of an atomic 3He impurity and an interstitial 4He atom in two- and three-dimensional solid 4He using path integral Monte Carlo (PIMC) simulation. We find that when a substitutional 3He impurity is introduced, the…
Properties of bosonic atoms in small systems with a periodic quasi one-dimensional circular toroidal lattice potential subjected to rotation are examined by performing exact diagonalization in a truncated many body space. The expansion of…
We study a two-dimensional fluid of dipolar hard disks by Monte Carlo simulations in a square with periodic boundary conditions and on the surface of a sphere. The theory of the dielectric constant and the asymptotic behaviour of the…
Recently there have been experimental indications that solid 4He might be a supersolid. We discuss the relation of supersolid behavior to ring exchange. The tunnelling frequencies for ring exchanges in quantum solids are calculated using…
We study the superfluid transition of $^4$He in aerogel by Monte Carlo simulations and finite size scaling analysis. Aerogel is a highly porous silica glass, which we model by a diffusion limited cluster aggregation model. The superfluid is…
X-ray diffraction experiments show that solid 4He grown in aerogel is highly polycrystalline, with a hcp crystal structure (as in bulk) and a crystallite size of approximately 100 nm. In contrast to the expectation that the highly…
Nearly a decade ago the old controversy about possible superfluid flow in the ground state of solid He4 was revived by the apparent experimental observation of such superflow. Although the experimentalists have recently retracted, very…
The thermo-mechanical effect in superfluid helium is used to create an initial chemical potential difference, $\Delta \mu_0$, across a solid $^4$He sample. This $\Delta \mu_0$ causes a flow of helium atoms from one reservoir filled with…
Low temperature structural and superfluid properties of $^4$He confined in cylindrical nanopores are theoretically investigated by means of first principle Quantum Monte Carlo (QMC) simulations. We vary the density of $^4$He inside the…
Using path-integral Quantum Monte Carlo we study the low-temperature phase diagram of a two-dimensional superconductor within a phenomenological model, where vortices have a finite mass and move in a dissipative environment modeled by a…
The high-pressure II-III phase transition in solid hydrogen is investigated using the random phase approximation and diffusion Monte Carlo. Good agreement between the methods is found confirming that an accurate treatment of exchange and…
The superfluid fraction of ideal and interacting inhomogeneous Bose gases with varying asymmetry is investigated at finite temperature using well-known properties of the harmonic oscillator as well as the essentially exact microscopic path…
We show how a ground state trial wavefunction of a Fermi liquid can be systematically improved introducing a sequence of renormalized coordinates through an iterative backflow transformation. We apply this scheme to calculate the ground…
Measurements of the moment of inertia by Kim and Chan have found that solid 4He acts like a supersolid at low temperatures. To understand the order in solid 4He, we have used Path Integral Monte Carlo to calculate the off-diagonal long…